Coating apparatus



April 1961 c. F. BROWN, JR., EI'AL 2,980,057

COATING APPARATUS 5 Sheets-Sheet 1 Filed Feb. 28, 1957 INVENTORS LOQlCS ATTORNEY April 1961 c. F. BROWN, JR., ETAL 2,980,057

COATING APPARATUS Filed Feb. 28, 1957 5 Sheets-Sheet 2 April 1961 c. F. BROWN, JR, El'AL 2,980,057

COATING APPARATUS Filed Feb. 28, 1957 5 Sheets-Sheet 5 2 22 INVENTORS 4 fiifi/w/ww,

BY k au. w mcs ATTORNEY April 18, 1961 c. F. BROWN, JR., ETAL COATING APPARATUS 5 Sheets-Sheet 4 Filed Feb. 28, 1957 April 1961 c. F. BROWN, JR., ET AL 2,980,057

COATING APPARATUS 5 Sheets-Sheet 5 Filed Feb. 28, 1957 INVENTOR5 25m .zl fi/um u,

2604M$ 15M Kn-k. E Loctcs ATTORNEY United States Patent COATING APPARATUS Carl F. Brown, Jr., and RobertG. Corbin, Huntingdon, Pa., assignors to JohnR.-Wald Company, Incorporated, Huntingdon, Pa., a corporation of Pennsylvania Filed Feb. 28, 1957, Ser.'No. 642,976 14 Claims. v(c1..11 s--r23 The present invention relates to coating apparatus. More particularly, the present invention relates to apparatus for coating continuously moving metal articles.

The present invention has particular application in the coating of metal articles such as automobile license plates or tags. In the conventional form of coating license plates, the background of the plate is coated a particular color by spraying the entire plate and the embossed letters or numbers are then coated a different color. Prior to the instant invention, the embossed numbers or letters of the license plates Were coated by manually placing the plate face up on a metal table. The plate was retained in position by some convenient means and a coating roller was then rolled over the embossed indicia to coat the indicia the desired color. Although these prior known coating machines are satisfactory for performing the coating operation, they are inefficient in operation and are therefore economically undesirable.

It is an object of the present invention to provide coating apparatus that is automatic in operation and is adapted to continuously coat a series of moving articles.

Another object of the present invention is to provide coating apparatus which includes magnetic means .for etfectively retaining thearticles to be coated in proper coating position. 2

Still another object of the present invention is to provide coating apparatus wherein the articles .to be coated are moved to the coating station by a continuously moving conveying means. a

Still another object of the present invention is to provide coating material transfer means that applies a uniform amount of coating material to the articles to be coated at the coating station.

Still another object of the present inventionis'to, provide a reservoir for the transfer means which includes means for effectively retaining the coating material within the reservoir.

Still another object of the present invention is to provide means for lubricating the conveying means whereby the articles to be coated are more freely transferred'to and from the coating station.

Other objects and the nature and advantages of'the instant invention will be apparent from thefollowing description taken in conjunction with vthe accompanying drawings, wherein:

Fig. 1 is a side elevational view of .the coating vapparatus embodied herein, a portion of the base housing being cut away; V

Fig. 2 is a top plan view of the coatingappar atus shown in Fig. l, a portion of the upper housing being cut away Fig. 5 is a top plan view of the apparatus with the coater head assembly removed and portions of the conveying assembly being broken away;

Fig. 6 is a vertical sectional view of a portion of the coater head assembly showing a modified coating retaining member;

Fig. 7 isa top plan view of the transfer assembly shown in Fig. 6 with portions btoken away; and

Fig; 8 is a perspective view of the coating retaining member that is employed with the transfer assembly illustrated in Figs. 6 and 7.

Referring now to the drawings and particularly Fig. 1, the coating machine embodied herein is illustrated and includes a basegenerally indicated at 10, a conveying assembly mounted on the base 10 and generally indicated at '12 and a coating transfer or coater head assembly mounted on said conveying assembly and generally indicated at 14.

The base 10 is provided for elevating the conveying assembly 12 but also houses the drive mechanism for the entire unit. As shown in Figs. 1 and 3, the base 10 includes a housing 16 that is formed with integral front, rear and side walls and a top wall 17 that is formed with an enlarged opening for alfording communication between the interior of the housing 16 and the conveying .Mounted within the housing 16 is' a platform 19 to which are secured vertical standards 20 and 22 (Fig. 3).

Secured to the standards 20, 22 are rods 24 which receive in sliding relation thereon a saddle mounting'ZG. Mounted on the saddle mounting 26is anelectricmotor '28 thatris adapted to move laterally therewith in response to rotary movement of a hand wheel 30. The lateral movement of the motor 28 is effected by rotationof a worm 32 that is connected to the hand wheel 30 at one end and threadedly engaged at the other end in a threaded opening formed in the saddle mounting 26.

Secured to the shaft of the motor 28 is a variable pitch pulley 34 that drives a pulley 36 through a belt 38. The pulley 36 is secured to an input shaft 40 of aspeed reducer 42 which, as shown in Fig. 3, also includes an output drive shaft 44. Secured to the outer end of the drive shaft 44 is a sprocket gear 46 that drives the conveying assembly 12 and coater head assembly 14 through a chain 48, the chain 48 extending upwardly through the opening in the top wall 17 into engagement with a sprocket 49 mounted in the conveying assembly 12. It is seen that the drive from the motor 28 to the chain drive 48 is positively maintained at all times and that movernent of the hand wheel 30 will cause the saddle mounting 26Ito move laterally, thereby altering the speed ratio between the pulleys 34'and 36, as desired.

,Mounted on the top wall 17 of the housing 16 is the conveying assembly '12 which includes a frame that generally cornprises a housing 50. The housing 50 includes vertical side plates 52 and 54 which define the main support for the conveying assembly and are secured to the 'top wall 17 of the base 10. As shown in Figs. 4 and 5, the. side plates are braced by a plurality of spaced tie rods 56 which add strength and rigidity to the'conveying assembly. The interior of the housing is normally enclosed and for this purpose a front cover member 58 and a rear cover member 60 are provided and are secured by suitable bolts to the side plates 52 and 54. As shown more clearly in Fig. 2, the front and rear cover members 58, 60 are formed in a generally U-shape configulend a finished appearance to the structure. The upper shelf portions of the cover members 58, 60 are laterally spaced to receive a conveyor belt 62 therebetween and terminate inwardly adjacent the coater head assembly 14.

As shown in Fig. 2, spaced guides 61 are mounted on the front cover member 58 and form means for guiding the plates to be coated onto the conveyor belt 62. Also fixed to the front cover member adjacent the entrance to the conveyor belt 62 are a series of metal wear plates 65 that are adapted to initially receive plates 191 as they are placed in readiness for loading onto the conveyor belt 62. i

As more clearly illustrated in Fig. 5, it is seen that the cover members 58,60 may be easily removed from engagement with the side plates 52, 54, thereby providing for convenient access to the interior of the housing 50.

The conveyor belt 62 is adapted to convey the articles to be coated to a coating station, which is located directly below the feeding assembly 14 and for this purpose includes a plurality of laterally extending metal slats 64 that are secured to sprocket chains 66 and 68 '(see Fig. 3). The sprocket chains 66 and 68 engage similar sprocket wheels 70, 72 and 74 which are mounted on shafts 76, 78 and 80, respectively. The shafts 76, 78 and 8d are journalled for rotation in suitable bearings 81 fixed to the side plates 52, 54, and collars 83 (Fig. formed integral with the sprocket wheels are fixed to the shafts 76, 78, 80 for retaining the sprocket wheels in fixed position. As shown in Fig. 3, the shaft 80 also has the sprocket wheel 49 mounted for rotation thereon and thereby transfers the drive from the sprocket chain 48 to the conveyor assembly. It is seen that the sprocket 1 wheel 49 transfers the drive from the speed reducer 42, output shaft 44, sprocket wheel 46 and chain 48 to the drive shaft 80 for driving the conveyor assembly 12 and the coater head assembly 14 as will be described hereinafter.

Since the coating machine described herein is adapted to be employed primarily for the coating of fiat metal articles, such as license plates or tags, and is adapted to particularly coat the embossed portions of the license plates, it is necessary that the license plates be fixed in firm face-to-face contact with the belt 62 during the coating operation. In order to maintain the license plates in firm surface engaging contact with the belt 62 as the embossed portions of the plates are being coated,

' a permanent magnet 82 is provided and as shown in Fig.

3 is U-shape in configuration and is secured to a magnet plate 84 with the open portion of the U facing upwardly and in intimate contact with the underside of the plate 84. The magnet plate 84 is mounted on a bracket 85 that includes upstanding members 86 which are secured to horizontal bed plates 88. The bed plates 88 are integrally joined to supports 90 which are, in turn, secured to the side plates 52, 54 (see Fig. 4). Mounted on the bracket 85 and positioned in contacting relation with the magnet plate 84 are longitudinally extending pole faces 92 and 94. As shown more clearly in Fig. 5, the pole faces 92, 94 extend substantially the length of the conveyor belt 62 and are spaced to extend substantially the width of the belt 62. Each of the pole faces is furthermore tapered so that the widest portion thereof overlies the magnet plate 84, the magnetic field thereby being greatest at this point. With the pole, faces 92, 94 constructed as shown, it is seen that during the coating operation, the metal license plates will be magnetically attracted to the pole faces since the belt slats 64 are also formed of metal and are therefore magnetized in the region of the pole faces. The license plates are thus magnetically pulled into firm face-to-face contact with the metal slats 64 of the belt 62 and are therefore maintained in a firm position on the belt 62 during the coating operation.

Since the magnetic attraction of the pole faces di- 4 minishes at the loading and discharge ends of the conveyor belt 62, the license plates are easily discharged from the conveyor belt at a discharge station located at the rear or extreme left of the apparatus, as viewed in Fig. 2. A relatively short inclined table 96 is located at the discharge station immediately adjacent the belt 62, being positioned between the side plates 52, 54 and receiving the finished coated plates thereon. Secured to the side plates 52, 54 and extending downwardly over the in clined table 96 is'a take-off grating or discharge hopper 98 over which the coated license plates slide and from which they are removed by the operator of the machine.

During the movement of the slats 64 of the belt 62 over the pole faces 92, 94, there is considerable friction developed between the contacting areas of the slats and the upper surfaces of the pole faces, and this is due to the strong magnetic attraction therebetween. In order to provide for freer movement of the slats 64 over the pole faces 92, 94 Without diminishing the magnetic attraction therebetween, a lubricating system is provided whereby the under surface of the slats are continuously wiped with a film of oil.

Referring now to Fig. 3, a slat lubricating system is shown and includes a hollow drum 99 that is loosely mounted on the shaft and is adapted to oscillate on the shaft during rotation thereof. The surface of the oil drum 99 is covered with a pervious material, such as felt, that is adapted to transmit oil externally supplied thereto to the undersurface of the slats 64 which make wiping contact therewith. In order to keep the felt surface of the drum 99 saturated with the lubricating oil, an oil fed nozzle 100, which is connected to an oil feed system (not shown) is conveniently supported above the drum 99 and is controlled to drop a constant supply of oil on the drum surface. It is seen that as the belt 62 is continuously moved during the coating operation, the slats 64 will contact the surface of the drum in wiping engagement therewith and a film of oil will be transferred to the undersurface of the slats.

It is further seen that the lubricated slats 64 offer less resistance to the magnetic action of the pole faces 92, 94 as the conveyor 62 continues to move, and the friction between the moving slats and the pole faces is decreased. However, the magnetic attraction of the pole faces 92, 94 is not diminished and the metal license plates that are to'be coated and that are placed on the slats 64 are magnetically retained in firm position thereon during the coating operation. In operation of the device, the license plates indicated at 101 in Fig. 2 are placed on the conveyor belt 62 with the embossed portions facing upwardly. The entire metal license plate 101 is then drawn downwardly in flat and tight engaging relation with the top surface of the slats 64 and in this position are best located for receiving the coating material from the coating transfer or coater head assembly 14.

It is also contemplated that the slats defining the conveyor belt 62 be formed of a non-magnetic material such as nylon, or the slats be replaced by an endless ribbon or belt of plastic or laminated material, and hence much of the friction inherently present as the slats 64 slide over the pole faces 92, 94 would be eliminated. In the modification suggested, the magnetic attractionof the pole faces for the metal, articles on the belt 62 would not be diminished in any way and the metal license tags positioned onthe non-magnetic slats would still be magnetically attracted to the pole faces and would accordingly be firmly fixed in position on the belt during the coating operation.

Referring now to Fig. 4, the coater head assembly 14 is illustrated and as shown includes a lower housing 102 and an upper housing 104 that is adjustably mounted on the lower housing 10-2 by means of cap screws 186 (shown in dotted lines). The entire ink feed or coater head assembly 14 is mounted on spaced cam blocks 108 each of which is secured to the side plates 52, 54, the lower :ihousing 102 making contact with the cam'blocks and fitting between the sideplates '52, 54. In order to locate and properly position the lover housing 102 on the cam blocks 108, locating blocks 110 are provided and are secured to the side plates 52, 54. Each of the locating blocks 110 is positioned adjacent a cam block 108 and is formed with a tapered upper portion, the tapered up- ,per portion serving to guide the lower housing 102 onto the surface of the articles beingncoated,

J u a o at on in-t e lowe housin 102 a e a -pair of spacedrollers 112 -114-whieh arerubber coated and thereby define the means for coating the articleson the moving conveyor belt 62. The rollers 112, 114 are positioned in the lower housing 102 such that the peripheral surface thereof is located in contacting relation with the embossed surfaces of the license plates 101 as they ,pass under the rollers on the moving conveyor belt 62.

The coating roller 114 is adapted to transfer the drive from the drive shaft 80 to the coating transfer assembly and as shown in Figs. 2, 3 and 4 is drivingly connected to the shaft 80 through a gearing system that includes a gear 116 mounted on the shaft 80 and rotatable therewith. Engaging the gear 116 is a gear 118 that is mounted on a shaft 119 journalled for rotation in the side plates 52, 54. The gear 11% engages an idler gear 120 that is mounted in a bracket 122, the bracket 122 being pivotally mounted on the shaft 112 and providing for pivotal movement of the idler gear 120 when the feed assembly 14 is adjusted vertically by the cam blocks 108. Engaging the idler gear 120 is a gear 124 that carries the coating roller 114. Drivingly connected to the gear 124 is a gear 126 that is carried by a shaft 127 of a steel pick-up roll 128 the shaft 127 being journalled for rotation in the upper housing 104. Engaging the pick-up roll 128 in contacting relation therewith is a steel fountain roll 130 that includes a shaft 131 that is journalled for rotation in the upper housing 104, the fountain roll shaft 130 having a gear 134 mounted for rotation thereon and engaging the gear 126. The gear 126 further engages a gear 136 that is secured to a shaft 138 journalled for rotation in the upper housing 104, the shaft 138 being carried by an oscillating roll 140 that contacts the pick-up roll 128 and is adapted to oscillate with respect thereto during the coating operation, as will hereinafter be described. It is seen that the twin coating rollers 112, 114 of the coater head 14 are driven through a series of gears from the conveyor mechanism and the ink transfer rolls defined by the pick-up roll 128, fountain roll 130 and oscillating or ink spreader roll 140 are interconnected through gearing to the coating rollers 112, 114 and are driven thereby.

Located at the ends of the pick-up roll 128 and the fountain roll 130 and extending therebetween are ink retaining guides 142, the space formed between the guides 142 and the pick-up and fountain rolls 123, 130 defining an ink hopper or reservoir 144. The ink is supplied to the reservoir 144 by a pressurized ink feed system that includes a nozzle 146 secured to a block 148 mounted on the top of the upper housing 104-. The nozzle 146 communicates with a pressure conduit 150 that is controlled by a manually operated valve 152. A pressure tank (not shown) is conveniently located adjacent the coating machine and supplies the coating ink under pressure to the conduit 150 during the coating operation. The valve 152 is adjusted during the coating operation to maintain a proper supply of ink in the hopper 144.

In order to obtain proper coating of the embossed portion of the license plates or tags being coated, it is necessary that the film of ink supplied to the twin coating rollers 112, 114 be maintained at a proper thickness. -.Thus, by keeping the. film thickness ata minimum, tackin ssand dry ng of he coating at r a i l e p ve ed- ;Ink thickness is controlled by adjusting the position of the fountain roll 130 with respect to the pick-up roll 128. Asshown in Fig. 4, the fountain roll 130 is mounted on spring loaded slides 154 which are adjustably moved by knurled lever screws 156. The position of the fountain roll 130 is thereby controlled by the screws 156 which move vthe fountain roll laterally with respect to the pick- ;up roll 128. The ink filrri thickness is thus controlled and ismaintained ata minimum for preventing splatter and feathering of the ink on the coated plates.

The ink ,coater assembly is completed by securing covers 158 and 160 in place on the top of the upper housng..10 sshown inFig- 4 t e c ve s 53, 0 are pr v ded with roun ed, u ncd edges a nap O the rods .162, the ods. 62 def n n upp t for h ink co t r assembly upp ho ng 04- In operation ofthe coating apparatus, the upper surface of the license plates or tags 101 is first sprayed with a coating of paint at a spraying station (not shown), after which a coating of reflex reflecting articles may be distributed'over the freshly coated surface. The plates are baked for a predetermined period of time and then placed on the loading end of the conveyor assembly 12 in contact with the meta-l slats 64 of the conveyor 62. Continuous movement of the conveyor belt ;62 transfers the plates 101 to the coating station beneath'the coater head assembly 14. The plates 101 are maintained in firm and flat position on the conveyor belt 62 due to the magnetic attraction of the pole faces 92, 94 and asthe plates 101 pass under the twin coating rollers 112, 114, a film of plate is then moved by the belt 62 under the coating roller 114 Where a second coat of ink is applied to the embossing. This double coating of ink on the plate embossing insures that the plate indicia will be properly coated and will be easily distinguished from the background coating that had been previously sprayed on the surface of the plate.

The ink supply is regulated by the screws 156 which control the position of the fountain roll 130 with respect to the pick-up roll 128 and thereby controls the thickness of the ink applied to the coating rollers 112, 114. The oscillating roller 140 is adapted to oscillate with respect to the pick-up roll 128 and thereby acts to evenly spread the ink supplied to the twin coating rollers 112, 114.

The position of the twin coating rollers 112, 114 with respect to the moving conveyor belt 62 is adjusted by regulating the cam blocks 108. Thus, the coating rollers 112, 114 may be moved into closer contact with the plate embossing as the rubber surfaces of the rollers Wear after periods of use. In order to maintain a constant drive to the coater head assembly when the cam blocks 108 are adjusted, the idler gear 120 is pivotally moved with the bracket 122 with respect to the gear 118. The pickup ro ll 128 may also be adjusted with respect to the coating rollers 112, 114 by the cap screws 106 as the coating rollers wear after continued use. Continued movement of the conveyor belt 62 carries the coated plates to the discharge end of the conveyor assembly where they are slidably moved onto the inclined table 96 and then into the discharge hopper 98 from which they are removed for further handling.

Referring now to Figs. 6-8, a modified form of the guides that define the ink hopper 144 are illustrated. It has been found that on occasion the ink supply has a tendency to leak through the color guides and in order to avoid this objectionable leakage, the pick-up roll 128 and fountain roll are formed with grooves 164 adjacent the ends thereof. A metallic, ceramic or plastic guide 166 isadaptedto fit in the grooves164:and for this pur- -p,ose;is formed with concave surfaces 168. that havev a radius of curvature similar to the radius of curvature of the curved portions of the grooves formed in the rolls 123 and 130. It is seen that the guides 166 fit snugly within the rolls 128 and 130 and thereby act to entrap the ink in the hopper 144 and prevent any leakage of the ink therefrom. The end portions of the guides 166 terminate in edges 170 that define scrapers which engage the sides of the grooves 164, the scraper maintaining a seal to effectively retain the ink in the hopper 144. The guides 166 are secured in place by bolts 172 that extend through a plate 174 and thereby retain the guides in contacting relation with the grooves 164 formed in pick-up roller 128 and fountain roller 130.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

What is claimed is:

1. In a device for coating flat ferrous metal articles, means for conveying said metal articles to a coating station, magnet means underlying said conveying means and being adapted to draw said metal articles into firm contact with said conveying means during the coating operation, said magnet means including a pair of pole faces that extend substantially the length of said conveying means and means for coating said metal articles, said coating means including coating rollers disposed above said conveying means and contacting said metal articles as they are conveyed thereunder, said coating rollers transferring coating'material onto said metal articles at said coating station.

2. In apparatus for coating ferrous metal articles, a

frame, means mounted on said frame for conveying said metal articles to a coating station, means for driving said conveying means, means for retaining said metal articles in positive engagement with said conveying means during the coating operation, said retaining means including a pair of longitudinally extending magnet pole faces disposed under said conveying means and extending substantially the length thereof, and means for coating said metal articles with a coating material, said coating means including vertically adjustable coating rollers, said coating rollers being located in series and being adapted to apply a dual coat of coating material to said metal articles. 7

3. In apparatus for coating the embossed portions of license plates formed of ferrous metal, a base, a conveying assembly mounted on said base, and a coater head assembly mounted on said conveying assembly, said conveying assembly comprising stationary support means, a conveyor belt including a plurality of magnetizable metal slats, a pair of flat magnet pole faces mounted on said support means and located under said slats and adapted to magnetically attract said license plates so that when said plates are placed on said conveyor belt, they are pulled into firm engagement with said slats, said magnet pole faces extending substantially the length of said conveyor belt, said coater head assembly including a pair of coating rollers mounted over said conveyor belt, and means for supplying said coating rollers with coating material, said coating rollers transferring said coating material to the embossed portions of said license plates as said license plates are moved thereunder on said conveyor belt.

4. In apparatus for coating the embossed portions of license plates as set forth in claim 3, which includes means for vertically adjusting the position of said coating rollers with respect to said conveyor belt, said adjusting means including cam blocks rotatably mounted on said conveying assembly and contacting said coater head assembly.

5. In a device for coating the embossed portions of ferrous metal license plates, a conveyor belt for corn veying said license plates to a coating station, said con anemone veyor belt including a plurality of transversely extending 6. In apparatus for coating fiat articles, a coating material transfer means comprising an upper and a lower housing, said upper housing being vertically adjustable with respect to said lower housing, a pair of coating rollers mounted in said lower housing and adapted to contact said fiat articles for transferring coating material thereto, a pick-up roller mounted for rotation in said upper housing and making contact with said coating rollers for transferring coating material thereto, a fountain roller mounted for rotation in said upper housing and contacting said pick-up roller, a coating material hopper thereby being defined between said pickup and fountain rollers, means for laterally adjusting said fountain roller with respect to said pick-up roller for controlling the thickness of the coating material transferred to said transfer rollers, means for evenly spreading said coating material on said pick-up roller, means for supplying coating material under pressure to said hopper, and means for confining said coating material Within said hopper, and a plurality of cam members engaging said lower housing for vertically adjusting the position thereof with respect to the articles being coated, thereby compensating for Wear of said coating rollers.

7. In apparatus as set forth in claim 6, wherein said confining means includes guides engaging said pick-u and fountain rollers adjacent the ends thereof.

8. In apparatus as set forth in claim 7, wherein said pick-up and fountain rollers are formed with grooves adjacent the ends thereof ,said guides snugly fitting into said grooves and thereby effectively retaining said coating material in said hopper.

9. In apparatus for coating fiat ferrous metal articles, a base housing a drive assembly, a conveying assembly mounted on said base and including stationary support means a conveyor belt operatively connected to said drive assembly and driven thereby, permanent magnet means mounted on said support means and positioned under said conveyor belt and adapted to magnetically attract the flat metal articles that are disposed on said conveyor belt, said metal articles thereby being securely retained in position for receiving a film of coating material thereon, said magnet means including spaced parallel pole faces that extend substantially the length of said conveyor belt, and a coater head assembly mounted over conveying assembly and including coating transfer means operatively connected to said drive assembly and driven thereby, said coating transfer means applying said coating material to said flat metal articles.

10. In apparatus as set forth in claim 9, wherein said conveying assembly includes a plurality of cam blocks that rotatably engage said coater head' assembly to vertically adjust said coater head assembly with respect to said conveyor belt.

11. In a device for coating the embossed portions of ferrous metal articles, a conveyor belt for conveying said metal articles to a coating station, stationary support means, magnetic means positioned immediately below the conveying portion of said conveyor belt and including a magnet mounted on said support means, a pair of longitudinally extending planular magnet pole faces mounted on said support means and extending substantially the length of said conveyor belt, a plurality of transversely extending flat slats mounted on said conveyor belt and slidably engaging said planular pole faces during the conveying operation, said slats being magnetizable metal and receiving said metal articles thereon for transfer to the coating station, said metal articles being retained in fixed flat position on said conveyor belt by the magnetic attraction of said pole faces located below said slats during the conveying and coating operations, means located below the conveying portion of said conveyor belt for making wiping contact with the under side of said slats and applying a lubricant thereto, said lubricant decreasing the frictional contact between said slats and pole faces during the conveying and coating operations.

:12. In apparatus for coating the embossed portions of ferrous metal license plates, a base, a conveying assembly mounted on said base, and a coater head assembly mounted on said conveying assembly, said conveying assemblyv comprising stationary support means, a conveyor belt including a plurality of magnetizable metal slats, a pair of flat magnet pole faces mounted on said support means and located under said slats and adapted to magnetically attract said license plates so that when said plates are placed on said conveyor belt, they are pulled into firm engagement with said slats, said magnet pole faces extending substantially the length of said conveyor belt, said coater head assembly including a pair-of coating rollers mounted over said conveyor belt, means for supplying said coating rollers with coating material, said coating rollers transferring said coating material to the embossed portions of said license plates as said license plates are moved thereunder on said conveyor belt, and means for lubricating the undersurfaces of said metal slats, whereby said slats are freely slidable over said magnet pole faces, said lubricating means including an oscillating hollow drum provided with a pervious surface for retaining therein a lubricating fluid fed thereto from an external source.

13. In apparatus for coating fiat ferrous metal articles, a base housing a drive assembly, a conveying assembly mounted on said base and including stationary support means, a conveyor belt operatively connected to said drive assembly and driven thereby, said conveyor belt including a plurality of metal slats, permanent magnet means mounted on said support means and positioned under said conveyor belt and adapted to magnetically attract the fiat metal articles that are disposed on said conveyor belt, said metal articles thereby being securely retained in position for receiving a film of coating material thereon, said magnet means including spaced parallel pole faces that extend substantially the length of said conveyor belt, said metal slats engaging said magnetmeans in sliding relation, and a coater head assembly mounted over conveying assembly and including coating transfer means operatively connected to said drive assembly and driven thereby, said coating transfer means applying said coating material to said fiat metal articles.

14. In apparatus for coating flat ferrous metal articles, a base housing a drive assembly, a conveying assembly mounted on said base and including stationary support means, a magnetizable conveyor belt operatively con nected to said drive assembly and driven thereby, permanent magnet means mounted on said support means and positioned under said conveyor belt and adapted to magnetically attract the fiat metal articles that are disposed on said conveyor belt, said metal articles thereby being securely retained in position for receiving a film of coating material thereon, said magnet means including spaced parallel pole faces that extend substantially the length of said conveyor belt, a coater head assembly mounted over conveying assembly and including coating transfer means operatively connected to said drive assembly and driven thereby, said coating transfer means applying said coating material to said flat metal articles, and means for lubrieating the underside of said conveyor belt whereby said conveyor belt is freely slidable over said magnet means, said lubricating means including an oscillating drum provided with a pervious surface for retaining lubricant therein, said surface making wiping contact with said conveyor belt for transferring lubricant thereto.

References Cited in the file of this patent UNITED STATES PATENTS 718,527 Rushworth Jan. 13, 1903 1,175,578 Adams Mar. 14, 1916 1,375,126 Willwerscheid Apr. 19, 1921 2,162,889 Hormel June 20, 1939 2,670,069 Dobkin Feb. 23, 1954 2,684,753 Kolbe et al. July 27, 1954 2,708,022 Pettigrew May 10, 1955 2,881,901 Zimmer Apr. 14, 1959 FOREIGN PATENTS 491,036 Canada Mar. 10, 1953 876,188 Germany May 11, 1953 1,122,473 France Sept. 7, 1956 

